This invention is concerned with an apparatus for use in shearing gobs from a vertical column of plastic material. For example, the apparatus may be used for shearing gobs of molten glass from a vertical column of molten glass issuing from a feeder, each gob being used for making a single article of glassware.
In a conventional apparatus for use in shearing gobs from a vertical column of plastic material, a first shearing blade is mounted on the end of an arm which is turnable about a vertical axis, a second shearing blade is mounted on a second arm for turning movement about the same or a parallel axis, and turning means is used to cause the arms to turn about the axis or axes so as to move the shearing blades between a condition in which one blade is on each side of the vertical column of plastic material and a condition in which the blades are in overlapping relationship having sheared through the vertical column. Conventionally, the turning means comprises a continuously rotating motor which acts on the arms via a cam which causes the arms to make only intermittent movements so that the column of plastic material has time to pass between the shearing blades before a gob is sheared therefrom. Due to inertia and other considerations, the conventional apparatuses are limited in the number of cuts they can achieve in a given time.
It is an object of the present invention to provide an apparatus for use in shearing gobs from a vertical column of plastic material in which higher numbers of gobs can be produced in a given time than by conventional shearing apparatus.